John eeece



x J. BEECE. Thread-Tension Device'fo'r Sewing Machines N0.164,035.Patented'Jun e1J875.

WITNESSES: I

' THE GRAPHIC Coil-i070 -LlTH-39'&M P ARK PLAOEJLY.

JOHN REEGE, OF STANSTEAD, CANADA, ASSIGNOR TO OZRO MORRILL, OF SAMEPLACE.

EMPROVEMENT IN THREADTENSION DEVlCES FOR $EWlNG=MACHINES.'

Specification forming part of Letters Patent No. 1 64,036, dated June 1,1875; application filed February 1, 1875.

To all whom it may concern:

Be it known that I, JOHN REEoE, of Stanstead, in the Province of Quebecand Dominion of Canada, have invented a new and Improved Thread-TensionDevice for Sewing- Machines; and I do hereby declare that the followingis a full, clear, and exact description of the same, reference being hadto the drawing, forming a part of this specification, in which- Figure 1is a side elevation. Fig. 2 is a transverse section through the cam.Fig. 3 is a longitudinal section.

My invention relates to an improvement in means for controlling thesupply of thread to the needle, the same consisting of springclamping-plates, a sliding pin or push-bar, a cam-grooved shaft, andranadjusting-screw, combined and arranged as hereinafter described.

Referring to the drawing, the thread a from the spool b is conductedbetween the two plates A and B, which form the clamp, and thence over orthrough necessary guide hooks or eyes 0 to the needle 6. The horizontalshaft 0, which drives the shuttle, or its functional equivalent, in asewing-machine, has a cam, E, formed on a portion of its length oppositethe clamp-plates A B. This portion of the shaft works in contact with asmall pin, G, whose outer end bears against the inner surface of theplate A, but passes freely through theplate B. The plate A is a spring,and presses firmly against the plate B, thus holding the threadimmovably during the greater portion of the revolution of the shaft-4.6., except when the cam E is acting on the pin G. When such action takesplace the free end of spring A is pushed away or separated from plate B,thus entirely releasing the thread, and allowing a sufficient length tobe drawn from the spool to form the stitch. The pin G then recedes, thespring A closes again against plate B, and the-thread is tightlyclamped, as before, till more thread is demanded for a new or the nextstitch, except as hereinafter stated.

It will be understood that the cloth, when moved along by the feed,determines the requisite amount of thread for a stitch, be it long orshort. It is after this, and just as the eye of the needle (in itsdescent) has passed through the cloth-plate, that the plates A B closetogether.

I thus dispense with and render wholly unnecessary the employment of anysupplementary tension or devices, the stitch being formed entirely byaid of this one clamping device, and perfectly, whatever be the lengthof thread required in consequence of difference in the thickness offabric or fineness of the thread itself.

The only adjustment of the spring-plates ever required is made at theshop, and to this end I provide a set-screw, t, to adjust the free endof plate B in relation to the shaft, and thus decrease or increase thetime of the separation between said parts A B. The screw t passesthrough both plates A B, and has a collar or shoulder formed on it,against which the free end of plate B rests, as shown in Fig. 3.

The exception hereinbefore made relates to a second opening of theplates, which occurs when the needle is at its lowest point, and atrest, and is instantaneous. The object of this second opening is setforth as follows, it being solely for the purpose of preventing theskipping of stitches: The bag orloop through which the shuttle or hookof a sewing-machine passes isformed by the ascent of the needle, which(the thread remaining stationary) causes the thread to bulge laterally.Now, if there be a strain on the thread, it will not remain stationary,but will retract and hug the needle, and consequently no bag or loopwill be formed, and a stitch will be skipped.

As my method of controlling the thread allows me to remove all butunavoidable tension, I am enabled to give the thread a chance (justbefore the formation of the bag or loop) to case itself of the strain orstretch, by drawing enough from the spool (the plates being separatedfor that purpose) to prevent the aforesaid retraction, and consequentabortion, of the bag or loop. The sudden release of the thread is causedby the form of the cam, which is less than a right angle, and by thearrangement of plate A, and free-sliding pin 2' therewith, in the mannerdescribed.

spring clamping-plate, A, and a sliding pin, G, with the shaft 0, havinga cam formed with an acute angle for acting on said plate and releasingthe thread, in the manner described.

3. The combination of the plates A B and the adjusting-screw t,substantially as set forth.

JOHN REECE.

Witnesses:

F. D. BUTTERFIELD, A. A. LEWIS.

